The impact of a sea bass (Dicentrarchus labrax L., 1758) farm on water quality and benthic community structure was investigated at a fish farm site in Engeceli Bay (western part of Izmir Bay) between April 2001 and February 2002. The characteristics of the water column in the fish farm were investigated in terms of physical and chemical parameters. Concentrations of nitrate, phosphate and ammonium ions in all sampling stations within the Bay were compared with the water quality parameters measured at the outer part of Izmir Bay (Eastern Aegean Sea). While there were significant differences from season to season of the levels of ammonium, orthophosphate, total phosphate and nitrite, there were no significant differences among stations. However, nitrate values and organic carbon contents showed significant differences among sampling stations. A reference station was selected to compare benthic groups. While the reference site is characterized by a sandy bottom with the lowest carbon and highest diversity values, the other stations with silty‐clay bottoms showed higher organic enrichment and lower diversity with increasing abundance of polychaeta. Organic enrichment and particle size of sediments were closely associated with faunal groups particularly with polychaeta and mollusca.

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SUMMARY: The ascophoran Bryozoa Celleporaria brunnea, a new record for the Mediterranean Sea, was found on Mytilus galloprovincialis collected in the inner part of Izmir Bay (Aegean Sea, Turkey) in September 2004. The species was previously reported from the Pacific coast of the United States. Its occurrence in the polluted inner part of Izmir Bay, near Alsancak Harbour, suggests that it has been newly introduced to the area, possibly via ship hulls. The morphological, ecological and zoogeographical characteristics of the species are given and discussed.

The Dodecanese region has a high prevalence of marine alien species due to its close proximity to the Suez Canal and associated Suez shipping lanes, as well as its location at biogeographical border between sub-tropical and tropical biota. This region is therefore very important for the early detection of alien species entering the Mediterranean Sea via the Suez Canal and it is imperative that monitoring of alien species is continued in order to assess the levels of biological invasion. We present results of marine alien surveys, carried out in April 2014 on the island of Rodos. Surveys were performed by a team of marine taxonomic experts and students as part of an EU wide training school, coordinated by the COST Action TD1209 “Alien Challenge”. A variety of survey methods were employed to cover a number of coastal habitats. These included: rapid assessment surveys of epibiota on artificial structures in harbours, rapid assessment snorkelling surveys of biota on sublittoral bedrock, and quantified fishing surveys (both boat-seine and trammel net fishing methods). A total of 33 alien and cryptogenic species were recorded across all the survey techniques. Of these species, 9 represented first records for Rodos: the foraminiferan Amphisorus hemprichii, the polychaetes Branchiomma bairdi, Dorvillea similis, Hydroides dirampha and Pseudonereis anomala, the molluscs Aplysia parvula, Chama pacifica and Septifer cumingii, and the bryozoan Hippopodina feegeensis. Of note the record of the Lessepsian invader Dorvillea similis represents the second record in the Mediterranean Sea. Alien fish species represented a small but notable proportion of the diversity, biomass and number of individuals in fishing catch of both fishing methods. All alien fish species observed were already known to be present in Rodos. The addition of species firstly recorded in this study brings the total number of marine alien and cryptogenic species in the Dodecanese region up to 129 species. The vast majority of these alien species have entered unaided via the Suez Canal, but an increasing number have been introduced through hull fouling or ballast water transfer from shipping. The results highlight the value of conducting marine alien surveys with teams of a diverse range of taxonomic expertise, both in its scientific output and student training